With the development of radio technologies, more and more radio technologies begin to be widely adopted. Particularly in order to meet multiple communication requirements of terminal clients, multiple radio technologies will be adopted simultaneously in a same intelligent terminal.
FIG. 1 is a diagram of a user equipment adopting two or more radio technologies simultaneously. As shown in FIG. 1, in a user equipment 100, three radio technologies are adopted. A sub-device 101 (or called sub-module) adopts Long Term Evolution (LTE) technology, a sub-device 102 (i.e., Wireless Local Area Network Station (WLAN STA)) adopts Wireless Local Area Network (WLAN) specified by the IEEE Std 802.11 specification, and a sub-device 103 adopts Bluetooth radio technology specified by the IEEE Std 802.15 specification. The three sub-devices in the user equipment 100 perform radio communication with peer ends corresponding to respective radio technologies, respectively. The sub-device 101 performs radio communication with an E-UTRAN Node B (LTE eNB) 104 through an air interface; the sub-device 102 performs radio communication with another WLAN STA device 105 through an air interface; and the sub-device 103 performs radio communication with another Bluetooth device 106 through an air interface.
In FIG. 1, the sub-device 101, the sub-device 102 and the sub-device 103 are connected with each other through an inter-radio interface, for example, the sub-device 101 is connected with the sub-device 102 through L101 and the sub-device 101 is connected with the sub-device 103 through L102. Alternatively, the three sub-devices are controlled by a common control device 107.
As the user equipment is too small in volume, if two or more radio technologies are set in a same user equipment simultaneously, it certainly means that spatial distance between the sub-devices on which the two or more radio technologies are set is very small, for example, a few centimeters. That is, it is unable to design a large enough spatial isolation between antenna ports used by the two or more radio technologies, as such, when the radio technologies in a same user equipment use adjacent bands, due to reasons such as out of band emission and spurious emissions, the reception of another radio technology sub-device will be interfered when one of the radio technology sub-devices is emitting, vice versa. Furthermore, such interference cannot be eliminated by the existing filters, so the communication quality of the radio technology sub-devices is influenced seriously. Herein, said interference is called in-device co-existence interference.
Taking the user equipment 100 shown in FIG. 1 as example, it is assumed that WLAN and Bluetooth use the Industrial, Scientific and Medical (ISM) band (2.4 GHz-2.5 GHz), wherein WLAN uses the frequency band 2.4 GHz-2.4835 GHz in the ISM band, and Bluetooth use the frequency band 2.4 GHz-2.497 GHz in the ISM band. The ISM band is adjacent to the LTE band 40 (Band40: 2.3 GHz-2.4 GHz) and the uplink band of the band 7 (Band7 UP: 2.5 GHz-2.57 GHz), as shown in FIG. 2.
If the sub-device 101 uses a Time Division Duplex (TDD) mode and just uses Band40, or, the sub-device 101 uses a Frequency Division Duplex (FDD) mode and just uses Band7 in the uplink, mutual interference will exist between the sub-device 101, the sub-device 102 and the sub-device 103. The specific interference is as shown in Table 1.
TABLE 1Interference between the LTE Band40 and the ISM bandISMThe lower frequencyInterfere the whole LTE Band40,interferesband of the ISM bandwith strong interference (largerLTE(for example, the lowerthan 50 dB)20 MHz frequency band)Other frequencyInterfere the higher frequency bandbands of the ISM bandof the LTE Band40 (for example,the higher 20 MHz frequencyband)LTEThe higherInterfere the whole ISM bandinterferesfrequency band of theISMBand40 (for example,the higher 30 MHzfrequency band)The other frequencyInterfere the lower frequency bandbands of the Band40of the ISM band (for example, thelower 20 MHz frequency band),with strong interference (largerthan 50 dB)Interference between the LTE Band7 UP and the ISM bandLTEThe lower frequencyInterfere the whole ISM frequencyinterferesband of the Band7 (forband, with strong interferenceISMexample, the lower(larger than 50 dB)10 MHz frequency band)The other frequencyInterfere the higher band of thebands of the Band7ISM band (for example, the higher30 MHz frequency band)As shown in FIG. 2, as the LTE Band7 is far away from the ISM band, the ISM frequency band will not interfere the downlink of the LTE Band7.
As shown in Table 1, in the in-device co-existence interference between the LTE and the ISM-related radio technologies, the LTE Band40 and the ISM interfere mutually; the LTE Band7 will interfere the ISM but will not be interfered by the ISM.
In the existing LTE system, LTE user equipment detects the interference by the measurement of the Reference Signal Received Quality (RSRQ). This kind of detection mechanism is applicable to an scenario where the network has known the interference source. Generally, the network may configure rational measurement evaluation and measurement report parameters according to the network planning and network optimization or under the support of the Self-Organising Networks (SON) functions, to determine whether the user equipment is interfered in a serving cell by the signal quality measurement result of the serving cell reported by the user equipment (UE) and the signal quality measurement result of the relative neighbouring cells. If the network determines that the UE is interfered, the Node B may guarantee the communication quality of the UE by the inter-cell interference coordination technology or by handing over the UE to a neighbouring cell. During the measurement for the UE in the existing LTE system, as interference from the outside of the device usually becomes stronger gradually, the measurement report reported to the Node B by the UE is a result that is obtained and filtered all of the measurement results within a period of time (320 ms, for example, even longer), to avoid the Ping-pong handover of the UE caused by the short jitter of the signal.
Different from such interference from the outside of the device, the in-device co-existence interference has burst property and strong interference. On one hand, as the turn on time of the ISM-related radio technologies completely depends on the action of the user, the interference has burst property; on the other hand, as the ISM-related radio technologies and the LTE are located in a same user equipment, the spatial isolation between the antenna ports thereof is very small, and the interference has strong interference property. Therefore, in a user equipment in which multiple radio technologies coexist, if the LTE UE adopts the existing interference detection mechanism, detection will be too slow, which influences the data transmission of the LTE, even causes calls lost. In addition, the existing interference detection mechanism of the LTE can only detect an event that the LTE is interfered, but it cannot detect an event that the LTE interferes other devices, the interference to the ISM-related radio technologies from the LTE cannot be solved, so that the data transmission of the ISM-related radio technologies in the device is influenced, even interrupted.
Obviously, the in-device co-existence interference inside a device adopting multiple radio technologies seriously reduces the communication quality of all radio technologies in the user equipment, and influences the communication experience of the user.